Verify RCOU number mapping to Motor Location

How do I easily verify which RCOU # corresponds to which motor on a quad? I think it would be reasonable to assume that the RCOU # maps to the Pixhawk output channel number, but in Mission Planner motor test this is not the case.

Frame_type, frame-class and Motor Test.

Are you saying the Frame_type/frame-class numbering is the same as Motor Test? In my experience this is not the case. Motor Test is clockwise numbering, while the frame type aligns with torque (cw / ccw first, then the ccw/cw).

No. Motor test runs the same order regardless of type and class. But running the test and reviewing the type and class set you know the order.

If I am looking at the logs and I see RCOU 3 is saturated, how do I figure out which motor that is?

I think it matches frame type, so RCOU 3 for an X-quad is the front-left motor, but dont know how to verify this.

If it’s Quad X 3 can only be the front left motor.


If it’s Betaflight X 3 is the rear left motor.

And so on…

ok, so it matches the frame type, not the motor test or anything else.

Right. Motor Test tells you that the motor order and direction are correct.